Solid oxide fuel cells monolithic

Dees DW, Balachandran U, Dorris SE, Heiberger JJ, McPheeters CC, and Picciolo JJ. Interfacial effects in monolithic solid oxide fuel cells. In Singhal SC, editor. Proceedings of the First International Symposium on Solid Oxide Fuel Cells, Pennington, NJ The Electrochemical Society, 1989 89(11) 317-321. 

N. Minh et al., "Monolithic Solid Oxide Fuel Cell Development Recent Technical Progress," AlliedSignal, Fuel Cell Seminar Program and Abstracts, 1992 Fuel Cell seminar, 1992. 

Thermal-Hydraulic Model of a Monolithic Solid Oxide Fuel Cell... 

S. Ahmed, C. McPheeters, and R. Kumar, Thermal-Hydraulic Model of a Monolithic Solid Oxide Fuel Cell, ... 

There are many chemically reacting flow situations in which a reactive stream flows interior to a channel or duct. Two such examples are illustrated in Figs. 1.4 and 1.6, which consider flow in a catalytic-combustion monolith [28,156,168,259,322] and in the channels of a solid-oxide fuel cell. Other examples include the catalytic converters in automobiles. Certainly there are many industrial chemical processes that involve reactive flow tubular reactors. Innovative new short-contact-time processes use flow in catalytic monoliths to convert raw hydrocarbons to higher-value chemical feedstocks [37,99,100,173,184,436, 447]. Certain types of chemical-vapor-deposition reactors use a channel to direct flow over a wafer where a thin film is grown or deposited [219]. Flow reactors used in the laboratory to study gas-phase chemical kinetics usually strive to achieve plug-flow conditions and to minimize wall-chemistry effects. Nevertheless, boundary-layer simulations can be used to verify the flow condition or to account for non-ideal behavior [147]. 

SOFC can be manufactured in different geometrical configurations, i.e. planar, tubular or monolithic. Regardless of the geometrical configuration, a solid oxide fuel cell is always composed of two porous electrodes (anode and cathode), a dense electrolyte, an anodic and a cathodic gas channel and two current collectors. For the sake of simplicity the planar configuration is taken as reference, as shown in Figure 3.1. 

Murthy S., Fedorov G, 2003. Radiation heat transfer analysis of the monolith type solid oxide fuel cell. Journal of Power Sources 124(2), 453—458. 

Ahmed S., McPheeters C., Kumar R. (1991) Thermal hydraulic model of a monolithic solid oxide fuel cell. Journal of the Electrochemical Society 138(9), 2712-2718. 

Minh N Q etal., 1993, Monolithic Solid Oxide Fuel Cells with Integral Manifolds. US Patent 5,526,499. 

Lenz et al. [73] described the development of a 3 kW monolithic steam-supported partial oxidation reactor for jet fuel, which was developed to supply a solid oxide fuel cell (SOFC). The prototype reactor was composed of a ceramic honeycomb monolith (400 cpsi) operated between 950 C at the reactor inlet and 700°C at the reactor outlet [74]. The radial temperature gradient amoimted to 50 K which was attributed to inhomogeneous mixing at the reactor inlet. The feed composition corresponded to S/C ratio of 1.75 and O/C ratio of 1.0 at 50 000 h GHSV. Under these conditions, about 12 vol.% of each carbon monoxide and carbon dioxide were detected in the reformate, while methane was below the detection limit. Later, Lenz et al. [74] described a combination of three monolithic reactors coated with platinum/rhodium catalyst switched in series for jet fuel autothermal reforming. An optimum S/C ratio of 1.5 and an optimum O/C ratio of 0.83 were determined. Under these conditions 78.5% efficiency at 50 000 h GHSV was achieved. The conversion did not exceed 92.5%. In the product of these... 

Figure 735 Tubular, monolithic and planar geometries of solid oxide fuel cells. Illustration courtesy of M. Muller (Muller, 2001).

Burt A.C., Celik I.B., Gemmen R.S., Smirnov A.V., 2003. Influence of radiative heat transfer on variation of cell voltage within a stack. ]nProceedngs of the 1st International Conference on Fuel Cell Science, Engineering and Technology, Rochester, NY, April 21-23, 2003. Murthy S., Fedorov G, 2003. Radiation heat transfer analysis of the monolith type solid oxide fuel cell. Journal of Power Sources 124(2), 453-458. 

B. Monolithic Solid Oxide Fuel Cells (MSOFCs)... 

FIGURE 12.25. Current-voltage characteristics of monolithic single solid oxide fuel cell at 1000°C using pure... 

As for MCFC, internal reforming in SOFCs is possible over the anode catalyst partial oxidation reactions and direct oxidation of the fuel have also been found to occur [24—28]. Different concepts for solid oxide fuel cells have been developed over the years. Flat plates have an easier stack possibility, while tubular designs have a smaller sealing problem. Monolithic plates and even single-chamber designs have been considered and investigated for SOFC use [29-31]. 

For cargo and passenger boats, conversion to fuel cells and electric drive will follow as a consequence of the more favorable economics of the lessened fuel consumption. Hence, the rate-determining step is the manufacture of sufficiently large fuel cells once more the prospects look good for the monolithic solid oxide cell. 

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